ASTM A811-03(2008)
(Specification)Standard Specification for Soft Magnetic Iron Parts Fabricated by Powder Metallurgy (P/M) Techniques
Standard Specification for Soft Magnetic Iron Parts Fabricated by Powder Metallurgy (P/M) Techniques
ABSTRACT
This specification covers soft magnetic iron parts fabricated by pressing and sintering of iron powder. The specification does not cover parts produced by metal injection molding. Parts produced to this specification shall have a minimum sintered density of 6.6 g/cm3 (6600 kg/m3) in the magnetically critical section of the part. Chemical requirements for the sintered part are given. Three grades distinguished by the measured maximum value of coercive field strength are defined. Apart from the required measurements of sintered density, chemical composition and coercive field strength, information on magnetic aging and its detection is given. Appendices containing magnetic and mechanical property data for a variety of sintering conditions are provided.
SCOPE
1.1 This specification covers parts produced from iron powder metallurgy materials.
1.2 This specification deals with P/M parts in the sintered or annealed condition. Should the sintered parts be subjected to any secondary operation that causes mechanical strain, such as machining or sizing, they should be resintered or annealed.
1.3 The values stated in customary (cgs-emu and inch-pound) units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units which are provided for information only and are not considered standard.
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Designation:A811 −03(Reapproved 2008)
Standard Specification for
Soft Magnetic Iron Parts Fabricated by Powder Metallurgy
(P/M) Techniques
This standard is issued under the fixed designation A811; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope Alloys by Various Combustion and Fusion Techniques
1.1 This specification covers parts produced from iron
3. Terminology
powder metallurgy materials.
3.1 The terms and symbols used in this specification are
1.2 This specification deals with P/M parts in the sintered or
defined in Terminology A340.
annealed condition. Should the sintered parts be subjected to
any secondary operation that causes mechanical strain, such as
4. Ordering Information
machining or sizing, they should be resintered or annealed.
4.1 Purchase orders for parts conforming to this specifica-
1.3 The values stated in customary (cgs-emu and inch-
tion shall include the following information:
pound) units are to be regarded as standard. The values given
4.1.1 Reference to this specification and year of issue/
in parentheses are mathematical conversions to SI units which
revision,
are provided for information only and are not considered
4.1.2 Reference to an applicable part drawing,
standard.
4.1.3 Quantity required,
4.1.4 Acritical cross section of the part shall be defined and
2. Referenced Documents
so indicated on the applicable part drawing.The location of the
critical section is by mutual agreement between the purchaser
2.1 ASTM Standards:
and the producer (6.2),
A34/A34M Practice for Sampling and Procurement Testing
4.1.5 Magnetic property requirements if they are other than
of Magnetic Materials
stated in Table 1,
A340 Terminology of Symbols and Definitions Relating to
4.1.6 Whethercertificationofchemicalanalysisormagnetic
Magnetic Testing
property evaluation is required (Sections 5 and 7),
A596/A596M Test Method for Direct-Current Magnetic
4.1.7 Marking and packaging requirements (Section 12),
Properties of Materials Using the Ballistic Method and
and
Ring Specimens
4.1.8 Exceptions to this specification or special require-
A773/A773M Test Method for dc Magnetic Properties of
ments such as functional testing as mutually agreed upon
Materials Using Ring and Permeameter Procedures with
between the producer and the purchaser.
dc Electronic Hysteresigraphs
B328 Test Method for Density, Oil Content, and Intercon-
5. Chemical Composition
nected Porosity of Sintered Metal Structural Parts and
5.1 The chemical composition of the parts shall conform to
Oil-Impregnated Bearings (Withdrawn 2009)
the requirements prescribed in Table 2.
E1019 Test Methods for Determination of Carbon, Sulfur,
Nitrogen, and Oxygen in Steel, Iron, Nickel, and Cobalt
5.2 Determination of metallic constituents shall be by a
method acceptable to both the producer and the purchaser.
Analysis of carbon, oxygen, sulfur, and nitrogen shall be done
This specification is under the jurisdiction of ASTM Committee A06 on
in accordance with Test Methods E1019.
Magnetic Properties and is the direct responsibility of Subcommittee A06.02 on
Material Specifications.
6. Sintered Density Requirements
Current edition approved Nov. 1, 2008. Published December 2008. Originally
approved in 1983. Last previous edition approved in 2003 as A811 – 03. DOI:
6.1 Magnetic and residual induction of P/M parts strongly
10.1520/A0811-03R08.
depend on density. The density of P/M parts is determined by
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
the compressibility of the powder, the compacting pressure,
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on and sintering practice (temperature, time, and atmosphere).
the ASTM website.
6.2 Parts produced in conformance with this specification
The last approved version of this historical standard is referenced on
www.astm.org. shall have a minimum sintered density of 6.6 g/cm (6600
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
A811−03 (2008)
TABLE 1 Maximum Coercive Field Strength Requirements
aging, the test ring(s) should be heated for either 100 h at 150
Grade Coercive Field Strength 6 5°C or 600 h at 100 6 5°C and the coercive field strength
1 1.8 Oe (140 A/m) remeasured. A change in coercive field strength of 10 % or
2 2.0 Oe (160 A/m)
more of the original value is evidence that aging has occurred.
3 2.3 Oe (180 A/m)
7.7 Since magnetic properties are strongly affected by
processconditions,refertoAppendixX1fortypicalvaluesand
TABLE 2 Chemical Requirements (weight percent)
explanatory notes.
Element %
8. Workmanship, Finish, and Appearance
Carbon, max 0.03
Oxygen, max 0.10
8.1 The parts shall be uniform in composition and uniform
Nitrogen, max 0.01
in density within critical sections.
A
Others 0.50, max
B
Iron balance
8.2 If parts are sectioned or fractured, there shall be no
A
Othersreferstotraceelementswhicharetoberegardedasincidentalandnot
readily recognizable defects.
deliberate additions.
B
Iron is the balance by difference. Quantitative analysis of this element is not
9. Sampling
required.
9.1 A lot shall consist of parts of the same form and
dimensions, produced from a single mixed powder batch and
from an unchanged process, without discontinuity in produc-
kg/m ) in the critical section of the part. The critical section
tion, and submitted for inspection at one time.
shall be defined by agreement between the purchaser and the
producer.
9.2 The purchaser and producer shall agree upon a repre-
sentative number of specimens for testing.
6.3 Sintered density shall be determined in accordance with
Test Method B328.
10. Rejection and Rehearing
7. Magnetic Property Requirements
10.1 Parts that fail to conform to the requirements of this
specification shall be rejected. Rejection should be reported to
7.1 BecauseofthenatureofP/Mpartsproduction,magnetic
the producer or supplier promptly and in writing. In case of
testing of each lot is not required by this specification.
dissatisfaction with the results of the test, the producer or
However, it is strongly recommended that the purchaser
supplier may make claim for a r
...
This document is not anASTM standard and is intended only to provide the user of anASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation:A 811–97 Designation: A 811 – 03 (Reapproved 2008)
Standard Specification for
Soft Magnetic Iron Parts Fabricated by Powder Metallurgy
(P/M) Techniques
This standard is issued under the fixed designation A 811; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 This specification covers parts produced from iron powder metallurgy materials.
1.2 This specification deals with P/M parts in the sintered or annealed condition. Should the sintered parts be subjected to any
secondary operation that causes mechanical strain, such as machining or sizing, they should be resintered or annealed.
1.3The values stated in either customary (cgs-emu and inch-pound) units or SI units are to be regarded separately as standard.
Within the text, the SI units are shown in brackets. The values stated in each system are not exact equivalents; therefore, each
system shall be used independently of the other. Combining values from the two systems may result in nonconformance with this
specification.
1.3 The values stated in customary (cgs-emu and inch-pound) units are to be regarded as standard. The values given in
parentheses are mathematical conversions to SI units which are provided for information only and are not considered standard.
2. Referenced Documents
2.1 ASTM Standards:
A 34/A 34M Practice for Sampling and Procurement Testing of Magnetic Materials Materials
A 340 Terminology of Symbols and Definitions Relating to Magnetic Testing Testing
A 596/A 596M Test Method for Direct-Current Magnetic Properties of Materials Using the Ballistic Method and Ring
Specimens Specimens
A 773/A 773M Test Method for D-Cdc Magnetic Properties of Materials Using Ring and Permeameter Procedures with D-Cdc
Electronic Hysteresigraphs
B 328 Test Method for Density, Oil Content, and Interconnected Porosity of Sintered Metal Structural Parts and Oil-
Impregnated Bearings Bearings
E 1019 Test Methods for Determination of Carbon, Sulfur, Nitrogen, and Oxygen in Steel and in Steel, Iron, Nickel, and Cobalt
Alloys by Various Combustion and Fusion Techniques
3. Terminology
3.1 The terms and symbols used in this specification are defined in Terminology A 340.
4. Ordering Information
4.1 Purchase orders for parts conforming to this specification shall include the following information.:
4.1.1 Reference to this specification and year of issue/revision.,
4.1.2 Reference to an applicable part drawing.drawing,
4.1.3 Quantity required. required,
4.1.4 A critical cross section of the part shall be defined and so indicated on the applicable part drawing. The location of the
critical section is by mutual agreement between the purchaser and the producer (6.2). ),
4.1.5 Magnetic property requirements if they are other than stated in Table 1. ,
4.1.6 Whether certification of chemical analysis or magnetic property evaluation is required (Sections 5 and 7). ),
4.1.7 Marking and packaging requirements (Section 12). ), and
4.1.8 Exceptions to this specification or special requirements such as functional testing as mutually agreed upon between the
producer and the purchaser.
This specification is under the jurisdiction of ASTM Committee A-6A06 on Magnetic Properties and is the direct responsibility of Subcommittee A06.02 on Material
Specifications.
CurrenteditionapprovedApril10,1997.Nov.1,2008.PublishedDecember1997.2008.OriginallypublishedasA811–83.approvedin1983.Lastpreviouseditionapproved
in 2003 as A 811 – 903.
For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at service@astm.org. For Annual Book ofASTM Standards
, Vol 03.04.volume information, refer to the standard’s Document Summary page on the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
A 811 – 03 (2008)
TABLE 1 Maximum Coercive Field Strength Requirements
Grade Coercive Field Strength
1 1.8 Oe [140 A/m]
1 1.8 Oe (140 A/m)
2 2.0 Oe [160 A/m]
2 2.0 Oe (160 A/m)
3 2.3 Oe [180 A/m]
3 2.3 Oe (180 A/m)
5. Chemical Composition
5.1 The chemical composition of the parts shall conform to the requirements prescribed in Table 2.
5.2 Determination of metallic constituents shall be by a method acceptable to both the producer and the purchaser.Analysis of
carbon, oxygen, sulfur, and nitrogen shall be done in accordance with Test Methods E 1019.
6. Sintered Density Requirements
6.1 Magnetic and residual induction of P/M parts strongly depend on density. The density of P/M parts is determined by the
compressibility of the powder, the compacting pressure, and sintering practice (temperature, time, and atmosphere).
3 (6600
6.2 Parts produced in conformance with this specification shall have a minimum sintered density of 6.6 g/cm [6600 kg/m
kg/m ]) in the critical section of the part.The critical section shall be defined by agreement between the purchaser and the producer.
6.3 Sintered density shall be determined in accordance with Test Method B 328.
7. Magnetic Property Requirements
7.1 Because of the nature of P/M parts production, magnetic testing of each lot is not required by this specification. However,
it is strongly recommended that the purchaser require the producer to conduct periodic magnetic evaluations and to certify such
results. Such magnetic property evaluations shall be conducted in the following manner.
7.2 Whenrequested,eachlotofpartsshouldbesinteredwithatleastoneandpreferablythreeringtestspecimenswhichcomply
with the geometric requirements listed in PracticeA 34/A 34M. The ring specimen(s) shall be produced from the same mixed lot
of powder used to produce the parts.
7.3 The magnetic properties shall be determined in accordance with Test Methods A 596/A 596M or A 773/A 773M.
7.4 For the purpose of this specification, only the coercive field strength determined from a maximum applied magnetic field
strength of 15 Oe [1200 A/m] (1200 A/m) needs to be determined. Other magnetic properties may be specified by mutual
agreement between the purchaser and the producer.
7.5 CoerciveFieldStrengthRequirements —Three grades, defined by coercive field strength, are stipulated by this specification
and are listed inTable 1.The coercive field strength requirement for Grade 3 was developed from interlaboratory study.The values
for Grades 1 and 2 are based on a literature review and are believed to reflect the current industry capabilities.
7.6 Magnetic Aging— Nitrogen introduced during sintering can cause time-dependent degradation of magnetic properties.
Therefore, when requested by the purchaser, the producer shall test for aging. To de
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